yeah, I had a packet smash behind a bottle in the beer fridge, and i just kept it cold, and once I wanted to brew.. took it out, warmed it in a warm water bath, and shook it. it inflated in like two hours tops... I thought it may explode- but then I thought that Wyeast probibly designs the packaging to take a fair amount of pressure before bursting.

yeah, I had a packet smash behind a bottle in the beer fridge, and i just kept it cold, and once I wanted to brew.. took it out, warmed it in a warm water bath, and shook it. it inflated in like two hours tops... I thought it may explode- but then I thought that Wyeast probibly designs the packaging to take a fair amount of pressure before bursting.

Yeah they have! Mine didn't explode even though I left it for 15 hours at 22C.